Refrigerant mixture comprising difluromethane, pentafluroethane and 1,1,1-trifluoroethane

ABSTRACT

A novel refrigerant composition useful as a substitute for HCFC-22, comprising a first constituent of difluoromethane (CH 2 F 2 , HFC-32); a second constituent of pentafluoroethane (CHF 2 CF 3 , HFC-125); a third constituent of 1,1,1-trifluoroethane (CH 3 CF 3 , HFC-143a); a fourth constituent selected from the group consisting of cyclopropane (C 3 H 6 , RC-270), 1,1,1,2,3,3,3-heptafluoropropane (CF 3 CHFCF 3 , HFC-227ea), 1,1,1,2,2-pentafluoropropane (CH 3 CF 2 CF 3 , HFC-245cb), isobutane (CH(CH 3 ) 2 CH 3 , R-600a), octafluorocyclobutane (C 4 F 8 , RC-318), 1,1,1,2,3,3-hexafluoropropane (CHF 2 CHFCF 3 , HFC-236ea), butane (C 4 H 10 , R-600), bis(difluoromethyl)ether (CHF 2 OCHF 2 , HFE-134) and pentafluoroethylmethylether (CF 3 CF 2 OCH 3 , HFE-245).

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a refrigerant mixture which is useful as a substitute for chlorodifluoromethane (CHClF₂, HCFC-22). More particularly, the present invention relates to a refrigerant composition which is useful as a substitute for HCFC-22, which comprises a first constituent of difluoromethane (CH₂F₂, HFC-32); a second constituent of pentafluoroethane (CHF₂CF₃, HFC-125); a third constituent of 1,1,1-trifluoroethane (CH₃CF₃, HFC-143a); a fourth constituent selected from the group consisting of cyclopropane (C₃H₆, RC-270), 1,1,1,2,3,3,3-heptafluoropropane (CF₃CHFCF₃, HFC-227ea), 1,1,1,2,2-pentafluoropropane (CH₃CF₂CF₃, HFC-245cb), isobutane (CH(CH₃)₂CH₃, R-600a), octafluorocyclobutane (C₄F₈, RC-318), 1,1,1,2,3,3-hexafluoropropane (CHF₂CHFCF₃, HFC-236ea), butane (C₄H₁₀, R-600), bis(difluoromethyl)ether (CHF₂OCHF₂, HFE-134) and pentafluoroethylmethylether (CF₃CF₂OCH₃, HFE-245).

[0003] 2. Description of the Background Art

[0004] As is well known, CFC compounds have been restricted in produciton and use in accordance with the Montreal Protocol because they have been found as a main factor in contributing to the destruction of the ozone layer. In advanced nations, the use of such CFC compounds has already been banned since 1996. It is also known that HCFC-based compounds such as HCFC-22 have considerable effects in causing damage to the ozone layer even though this effect is less severe than those of the CFC compounds. For this reason, a restriction has been made to gradually reduce the use of such HCFC-based compounds. A plan has also been made to ban the use of HCFC-based compounds about the year 2020.

[0005] This has resulted in a number of world-wide research efforts to produce substitute materials coping with the restriction in use of HCFC-22 which will be more severe in the future. The representative examples of a substitute refrigerant mixtures are HFC-407C and HFC-410A proposed by the American Society of Heating. Refrigerating and Air-Conditioning Engineers (ASHRAE). HFC-407C is a refrigerant mixture of HFC-32/125/134a in a ratio of 23/25/52 (based on weight percent). Meanwhile, HFC-410A is a refrigerant mixture of HFC-32/125 in a ratio of 50/50 (based on weight percent).

[0006] In addition, U.S. Pat. No. 5,080,823 discloses a mixed refrigerant composition of HFC-143a/opropane (C₃H₈), U.S. Pat. No. 5,185,094: HFC-32/1251134a, U.S. Pat. No. 5,211,867: HFC-125/143a, U.S. Pat. No. 5,234,613: HFC-32/propane, U.S. Pat. No. 5,236,611: PFC-218/HFC-143a, U.S. Pat. No. 5,290,466: HFC-32/134a/134, U.S. Pat. No. 5,340,490: HFC-23/CO₂ or HFC-23/116/CO₂, U.S. Pat. No. 5,403,504: HFC-125/32, U.S. Pat. No. 5,429,760: HFC-23/134a, U.S. Pat. No. 5,538,660: HFC-32/HFC-134a/PFC-14 or HFC-32/HFC-134a/PFC-218, and U.S. Pat. No. 5,643,492: HFC-32/125/134a.

[0007] Also, Japanese Patent Laid-open Publication No. 172386/1991 discloses a mixed refrigerant composition of HFC-32/125/152, Japanese Patent Laid-open Publication No. 170594/1991: HFC-23/125/134a, Japanese Patent Laid-open Publication No. 170592/1991: HFC-32/143a/152a, Japanese Patent Laid-open Publication No. 170593/1991: HFC-23/125/32, Japanese Patent Laid-open Publication No. 170591/1991: HFC-23/143a/134a, Japanese Patent Laid-open Publication No. 170590/1991: HFC-125/134a/32, Japanese Patent Laid-open Publication No. 170589/1991: HFC-23/143a/152a, Japanese Patent Laid-open Publication No. 170588/1991: HFC-125/143a/134a, Japanese Patent Laid-open Publication No. 170587/1991: HFC-32/134a/152a, Japanese Patent Laid-open Publication No. 170586/1991: HFC-32/143a/134a, Japanese Patent Laid-open Publication No. 170585/1991: HFC-32/125/134a, Japanese Patent Laid-open Publication No. 170584/1991: HFC-23/134a/152a, Japanese Patent Laid-open Publication No. 170583/1991: HFC-125/143a/32, Japanese Patent Laid-open Publication No. 222893/1992: HFC-32/125, Japanese Patent Laid-open Publication No. 154887/1992: HFC-134/152a, Japanese Patent Laid-open Publication No. 117645/1993: HFC-23/134a/propane, Japanese Patent Laid-open Publication No. 117643/1993: HFC-125/134a/propane, Japanese Patent Laid-open Publication No. 65561/1994: HFC-23/152a/PFC-218, Japanese Patent Laid-Open Publication No. 128872/1994: HFC-32/PFC-218, Japanese Patent Laid-Open Publication No. 220433/1994: HFC-32/125/RC-318, Japanese Patent Laid-Open Publication No. 173462/1995: HFC-143a/125/134a/heptane (C₇H₁₆), Japanese Patent Laid-open Publication No. 176537/1996: PFC-218/RC-270/HFC-152a, Japanese Patent Laid-open Publication No. 151569/1996: propane/RC-270/HFC-34a, Japanese Patent Laid-open Publication No. 127767/1996: HFC-32/134a/RC-318, Japanese Patent Laid-open Publication No. 25480/1997: HFC-32/134a/125/isobutane, Japanese Patent Laid-open Publication No. 59611/1997: HFC-134a/isobutane, Japanese Patent Laid-Open Publication No. 208941/1997: HFC-32/152a/125/RC-270, and Japanese Patent Laid-open Publication No. 221664/1997: HFC-125/143a/134a/RC-270.

[0008] Also, Korean Patent Publication No. 93-10514 (Application No. 90-19594) discloses a mixed refrigerant composition of HFC-23/132/152a, HFC-23/125/152a, HFC-32/143a/152a, HFC-125/143a/152a, HFC-32/125/125a, HFC-23/143a/152a, or HFC-23/1251152a, Korean Patent Publication No. 93-10515 (Application No. 90-19596): HFC-23/32/134, HFC-23132/134a, HFC-23/125/134a, HFC-23/125/134, HFC-32/125/134, HFC-23/143a/134a, HFC-32/125/134a, HFC-125/143a/134a, or HFC-125/143a/134, Korean Patent Laid-Open Publication No. 96-4485 (Application No. 95-21221): HFC-321231134a, Korean patent Laid-open Publication No. 95-704438 (Application No. 95-701865): HFC-32/125/134a, Korean patent Laid-open Publication No. 96-701168 (Application No. 95-704038): HFC-227ea/HFC-152a, and Korean Patent Laid-open Publication No. 97-704853 (Application No. 97-700436): HFC-134a/HCFC-124/butane.

SUMMARY OF THE INVENTION

[0009] Therefore, an object of the present invention is to provide a novel refrigerant mixture which is useful as a substitute for HCFC-22. That is, the present invention has an object to provide a refrigerant composition produced by mixing additionally one component of RC-270, HFC-227ea, HFC-245cb, R-600a, RC-318, HFC-236ea, R-600, HFE-134 and HFE-245 with a mixture of HFC-32, HFC-125 and HFC-143a, thereby producing a composition capable of exhibiting properties similar to HCFC-22.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention relates to a refrigerant composition which is useful as a substitute for HCFC-22, which comprises a first constituent of difluoromethane (CH₂F₂, HFC-32); a second constituent of pentafluoroethane (CHF₂CF₃, HFC-125); a third constituent of 1,1,1-trifluoroethane (CH₃CF₃, HFC-143a); a fourth constituent selected from the group consisting of cyclopropane (C₃H₆, RC-270), 1,1,1,2,3,3,3-heptafluoropropane (CF₃CHFCF₃, HFC-227ea), 1,1,1,2,2-pentafluoropropane (CH₃CF₂CF₃, HFC-245cb), isobutane (CH(CH₃)₂CH₃, R-600a), octafluorocyclobutane (C₄F₈, RC-318), 1,1,1,2,3,3-hexafluoropropane (CHF₂CHFCF₃, HFC-236ea), butane (C₄H₁₀, R-600), bis(difluoromethyl)ether (CHF₂OCHF₂, HFE-134) and pentafluoroethylmethylether (CF₃CF₂OCH₃, HFE-245).

[0011] It is preferred that the refrigerant composition of the present invention comprises a first constituent of 15 to 95% by weight difluoromethane (CH₂F₂, HFC-32); a second constituent of an amount up to 60% by weight pentafluoroethane (CHF₂CF₃, HFC-125); a third constituent of an amount up to 70% by weight 1,1,1-trifluoroethane (CH₃CF₃, HFC-143a); a fourth constituent of an amount up to 50% by weight comprising one selected from the group consisting of cyclopropane (C₃H₆, RC-270), 1,1,1,2,3,3,3-heptafluoropropane (CF₃CHFCF₃, HFC-227ea), 1,1,1,2,2-pentafluoropropane (CH₃CF₂CF₃, HFC-245cb), isobutane (CH(CH₃)₂CH₃, R-600a), octafluorocyclobutane (C₄F₈, RC-318), 1,1,1,2,3,3-hexafluoropropane (CHF₂CHFCF₃, HFC-236ea), butane (C₄H₁₀, R-600), bis(difluoromethyl)ether (CHF₂OCHF₂, HFE-134) and pentafluoroethylmethylether (CF₃CF₂OCH₃, HFE-245).

[0012] In accordance with the present invention, the refrigerant composition as mentioned above is applied to a refrigeration system which comprises a compressor, a condenser, an expansion valve, and an evaporator in order to evaluate the coefficient of performance (COP), the volumetric capacity of refrigereant (VC), and pressures in the compressor and evaporator. The novel refrigerant mixture according to the present invention is evaluated to be substantially equivalent to HFC-407C or HFC-410A in terms of performance. Accordingly, the refrigerant mixture of the present invention is useful as a substitute for HCFC-22.

[0013] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and RC-270, the composition comprises 15 to 60% by weight of HFC-32, an amount up to 50% by weight of HFC-125, 20 to 70% by weight of HFC-143a and an amount up to 15% by weight of RC-270, and preferably, the composition comprises 25 to 45% by weight of HFC-32, 2 to 35% by weight of HFC-125, 28 to 60% by weight of HFC-143a and an amount up to 10% by weight of RC-270.

[0014] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and HFC-227a, the composition comprises 20 to 60% by weight of HFC-32, an amount up to 60% by weight of HFC-125, an amount up to 70% by weight of HFC-143a and an amount up to 50% by weight of HFC-227a, and preferably, the composition comprises 28 to 50% by weight of HFC-32, 2 to 50% by weight of HFC-125, 5 to 60% by weight of HFC-143a and an amount up to 40% by weight of HFC-227ea.

[0015] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and HFC-245cb, the composition comprises 20 to 90% by weight of HFC-32, an amount up to 60% by weight of HFC-125, an amount up to 60% by weight of HFC-143a and an amount up to 50% by weight of HFC-245cb, and preferably, the composition comprises 30 to 85% by weight of HFC-32, 2 to 45% by weight of HFC-125, 3 to 50% by weight of HFC-143a and an amount up to 40% by weight of HFC-245cb.

[0016] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and R-600a, the composition comprises 30-60% by weight of HFC-32, an amount up to 45% by weight of HFC-125, 15 to 50% by weight of HFC-143a and an amount up to 20% by weight of R-600a, and preferably, the composition comprises 38 to 50% by weight of HFC-32, 5 to 35% by weight of HFC-125, 20 to 43% by weight of HFC-143a and an amount up to 15% by weight of R-600a.

[0017] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and RC-318, the composition comprises 20 to 60% by weight of HFC-32, an amount up to 45% by weight of HFC-125, 10 to 50% by weight of HFC-143a and an amount up to 20% by weight of RC-318, and preferably, the composition comprises 30 to 48% by weight of HFC-32, 10 to 35% by weight of HFC-125, 20 to 40% by weight of HFC-143a and an amount up to 15% by weight of RC-318.

[0018] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and HFC-236ea, the composition comprises 20 to 85% by weight of HFC-32, an amount up to 40% by weight of HFC-125, an amount up to 60% by weight of HFC-143a and an amount up to 30% by weight of HFC-236ea, and preferably, the composition comprises 30 to 75% by weight of HFC-32, 5 to 30% by weight of HFC-125, 5 to 48% by weight of HFC-143a and an amount up to 20% by weight of HFC-236ea.

[0019] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and R-600, the composition comprises 25 to 70% by weight of HFC-32, an amount up to 60% by weight of HFC-125, an amount up to 40% by weight of HFC-143a and an amount up to 20% by weight of R-600, and preferably, the composition comprises 35 to 60% by weight of HFC-32, 5 to 50% by weight of HFC-125, 5 to 33% by weight of HFC-143a and an amount up to 12% by weight of R-600.

[0020] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and HFE-134, the composition comprises 30 to 95% by weight of HFC-32, an amount up to 50% by weight of HFC-125, an amount up to 40% by weight of HFC-143a and an amount up to 15% by weight of HFE-134, and preferably, the composition comprises 40 to 88% by weight of HFC-32, 2 to 40% by weight of HFC-125, 2 to 30% by weight of HFC-143a and an amount up IS to 10% by weight of HFE-134.

[0021] Where the refrigerant composition of the present invention includes HFC-32, HFC-125, HFC-143a and HFE-245, the composition comprises 30 to 90% by weight of HFC-32, an amount up to 50% by weight of HFC-125, an amount up to 45% by weight of HFC-143a and an amount up to 15% by weight of HFE-245, and preferably, the composition comprises 40 to 85% by weight of HFC-32, 5 to 40% by weight of HFC-125, 5 to 38% by weight of HFC-143a and an amount up to 10% by weight of HFE-245.

[0022] The present invention will now be described in more detail referring to the following examples. It is to be understood that these examples are merely illustrative and it is not intended to limit the scope of the present invention to these examples.

EXAMPLE

[0023] Evaluation of Performance of Refrigerant Composition

[0024] In order to evaluate the performance of the refrigerant mixture according to the present invention, a refrigeration system including a compressor, a condenser, an expansion valve, and an evaporator was used which has the following performance evaluation conditions:

[0025] Refrigeration capacity: 2 kW

[0026] Overall Heat Transfer coefficient in evaporator (UA): 0.20 kW/K

[0027] Overall Heat Transfer coefficient in condenser (UA): 0.24 kW/K

[0028] Degree of subcooling in condenser: 5° C.

[0029] Degree of superheating in evaporator: 5° C.

[0030] Efficiency of compressor: 0.8

[0031] Temperature of secondary fluid at inlet of condenser: 25° C.

[0032] Temperature of secondary fluid at outlet of condenser: 35° C.

[0033] Temperature of secondary fluid at inlet of evaporator: 15° C.

[0034] Temperature of secondary fluid at outlet of evaporator: 5° C.

[0035] Under the above conditions, the refrigerant compositions according to the present invention were compared to HCFC-22, HFC-407C and HFC410A in terms of the main factors for evaluating the refrigerant performance, that is, the coefficient of performance (COP), the volumetric capacity of refrigerant (VC), and evaporator pressure (P_(L)), and condenser pressure (P_(H)).

[0036] Comparative Examples 1 to 3

[0037] HCFC-22, HFC-407C and HFC-410A compared to the refrigerant compositions of the present invention have the following evaluated performances. TABLE 1 Evaluated performance of HGFG-22, HFC-407C and HFC-410A Comparative HCFC-22 HFC-32 HFC-125 HFC-134a VC P_(L) P_(H) example No. refrigerant (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 HCFC-22 100 — — — 5.45 3338 455 1254 2 HFC-407C — 23 25 52 4.98 3412 460 1445 3 HFC-410A — 50 50 — 5.31 5117 730 1993

[0038] Referring to Table 1, it can be seen that HFC-407C exhibits a COP slightly less than that of HCFC-22 while exhibiting a VC and pressures similar to those of HCFC-22. On the other hand, HFC410A has a COP similar to that of HCFC-22 while exhibiting pressures slightly higher than those of HCFC-22. It should be noted that a composition exhibiting a refrigerant performance defined as above is useful as a substitute refrigerant for HCFC-22. Accordingly, the performances of the refrigerant mixtures according to the present invention were evaluated and compared with the above evaluated results.

Example 1 Evaluation of Performance of Refrigerant Mixture of HFC-32/HFC-125/HFC-143a/RC-270

[0039] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/RC-270 at different weight percent of each constituents are described in Table 2, respectively. Referring to Table 2, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 2 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/RC-270 Composition HFC-32 HFC-125 HFC-143a RC-270 VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 40 30 30 0 5.20 4797 701 1919 2 30 35 30 5 5.06 4702 714 1949 3 35 30 30 5 5.09 4820 726 1975 4 25 35 35 5 4.98 4548 698 1923 5 40 30 28 2 5.17 4868 718 1957 6 42 25 30 3 5.18 4929 728 1973 7 42 23 32 3 5.18 4922 728 1970 8 42 18 37 3 5.20 4910 726 1959 9 42 10 45 3 5.20 4889 724 1948 10 42 5 50 3 5.20 4877 724 1942 11 42 0 55 3 5.20 4865 723 1937 12 45 0 55 0 5.26 4814 702 1891 13 33 0 60 7 5.11 4759 726 1941 14 33 0 58 7 5.11 4761 727 1942 15 28 2 60 10 5.04 4677 725 1940

Example 2 Evaluation of Performance of Refrigerant Mixture of HFC-32/HFC-125/HFC-143a/HFC-227ea

[0040] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/HFC-227ea at different weight percent of each constituents are described in Table 3, respectively. Referring to Table 3, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 3 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/HFC-277ea Composition HFC-32 HFC-125 HFC-143a HFC-227ea VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 28 2 60 10 5.04 4322 644 1803 2 35 0 60 5 5.14 4554 673 1847 3 45 10 45 0 5.26 4841 705 1904 4 30 30 35 5 5.06 4493 667 1865 5 30 40 28 2 5.06 4554 677 1891 6 40 5 50 5 5.20 4688 687 1875 7 35 33 25 7 5.13 4631 679 1891 8 40 15 30 15 5.18 4642 674 1872 9 50 15 15 20 5.26 4866 695 1917 10 45 20 10 25 5.17 4705 673 1897 11 50 20 0 30 5.22 4807 681 1918 12 48 7 5 40 5.09 4572 649 1875 13 35 45 12 8 5.11 4670 684 1919 14 40 50 7 3 5.18 4870 708 1962 15 40 5 50 3 5.20 4688 687 1875

Example 3 Evaluation of performance of Refrigerant Mixture of HFC-32/HFC-125/HFC-143a/HFC-245cb

[0041] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/HFC-245cb at different weight percent of each constituents are described in Table 4, respectively. Referring to Table 4, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 4 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/HFC-245cb Composition HFC-32 HFC-125 HFC-143a HFC-245cb VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 40 5 50 5 5.19 4633 676 1854 2 30 40 20 10 4.99 4360 641 1839 3 50 20 10 20 5.20 4630 652 1843 4 60 10 5 25 5.25 4720 655 1847 5 70 2 13 15 5.41 5040 701 1899 6 80 2 3 15 5.47 5180 712 1917 7 85 0 0 15 5.51 5235 716 1916 8 45 30 15 10 5.22 4739 678 1886 9 45 45 8 2 5.24 4946 712 1959 10 55 8 30 7 5.35 4927 701 1895 11 50 10 40 0 5.31 4940 714 1919 12 60 5 5 30 5.21 4908 638 1822 13 50 6 4 40 5.03 4180 576 1732

Example 4 Evaluation of Performance of Refrigerant Mixture of HFC-32/HFC-125/HFC-143a/R-600a

[0042] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/R-600a at different weight percent of each constituents are described in Table 5, respectively. Referring to Table 5, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 5 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/R-600a Composition HFC-32 HFC-125 HFC-143a R-600a VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 40 20 30 10 5.08 4722 716 1947 2 45 10 40 5 5.20 4887 726 1953 3 40 30 30 0 5.20 4797 701 1919 4 38 35 20 7 5.10 4748 714 1955 5 48 15 35 2 5.26 4951 723 1946 6 50 5 43 2 5.28 4963 724 1940 7 45 0 40 15 5.02 4673 714 1946

Example 5 Evaluation of Performance of Refrigerant Mixture of HFC-32/HFC-125/HFC-143a/RC-318

[0043] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/RC-318 at different weight percent of each constituents are described in Table 6, respectively. Referring to Table 6, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 6 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/RC-318 Composition HFC-32 HFC-125 HFC-143a RC-318 VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 35 30 25 10 5.11 4791 716 1970 2 45 20 30 5 5.23 4955 724 1967 3 48 10 40 2 5.28 4938 718 1933 4 30 15 40 15 5.00 4623 705 1952 5 40 30 30 0 5.20 4797 701 1919 6 43 0 50 7 5.22 4883 721 1943 7 40 35 20 5 5.17 4890 719 1972

Example 6 Evaluation of Performance of Refrigerant Mixture of HFC-32/HFC-125/HFC-143a/HFC-236ea

[0044] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/HFC-236ea at different weight percent of each constituents are described in Table 7, respectively. Referring to Table 7, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 3 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/HFC-236ea Composition HFC-32 HFC-125 HFC-143a HFC-236ea VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 40 20 30 10 5.06 4487 646 1844 2 55 30 10 5 5.31 5076 722 1972 3 30 20 48 2 5.08 4467 663 1842 4 60 5 20 15 5.20 4781 671 1884 5 70 10 0 20 5.13 4789 661 1899 6 35 18 40 7 5.08 4457 650 1832 7 75 0 5 20 5.22 4902 677 1904 8 50 25 25 0 5.31 4994 718 1941

Example 7 Evaluation of Performance of Refrigerant Mixture of HFC-32HFC-125/HFC-143a/R-600

[0045] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/R-600 at different weight percent of each constituents are described in Table 8, respectively. Referring to Table 8, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 8 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/R-600 Composition HFC-32 HFC-125 HFC-143a RC-600 VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 40 25 30 5 5.14 4708 698 1911 2 50 20 20 10 5.09 4711 693 1920 3 55 10 33 2 5.34 5042 728 1945 4 53 15 25 7 5.28 4970 726 1948 5 35 30 32 3 5.13 4635 689 1893 6 60 0 28 12 5.10 4797 705 1938 7 45 40 10 5 5.21 4886 715 1954 8 45 50 0 5 5.20 4920 717 1972 9 40 45 15 0 5.19 4859 708 1951

Example 8 Evaluation of Performance of Refrigerant Mixture of HFC-32/HFC-125/HFC-143a/HFE-134

[0046] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/HFE-134 at different weight percent of each constituents are described in Table 9, respectively. Referring to Table 9, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 9 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/HFE-134 Composition HFC-32 HFC-125 HFC-143a HFE-134 VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 70 20 5 5 5.21 4904 675 1904 2 80 10 2 8 5.09 4766 647 1878 3 85 5 0 10 5.02 4665 629 1857 4 88 0 10 2 5.42 5248 721 1938 5 65 15 15 5 5.18 4815 669 1890 6 75 2 20 3 5.72 5054 702 1917 7 60 8 30 2 5.30 4950 700 1909 8 50 30 15 5 5.10 4619 649 1865 9 40 40 15 5 4.99 4440 632 1847 10 50 25 25 0 5.31 4994 718 1941

Example 9 Evaluation of performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/HFE-245

[0047] The evaluated performances of the refrigerant mixture comprising HFC-32/HFC-125/HFC-143a/HFE-245 at different weight percent of each constituents are described in Table 10, respectively. Referring to Table 10, it can be found that the performance of the compositions indicated in each item of Table 2 fall within the ranges between those of HFC407C and HFC-410A, so that the tested refrigerant mixture is useful as a substitute for HCFC-22. TABLE 10 Evaluated performance of refrigerant mixture of HFC-32/HFC-125/HFC-143a/HFE-245 Composition HFC-32 HFC-125 HFC-143a HFE-245 VC P_(L) P_(H) No. (wt %) (wt %) (wt %) (wt %) COP (kJ/m³) (kPa) (kPa) 1 40 40 15 5 5.03 4545 655 1881 2 80 5 5 10 5.10 4868 674 1921 3 70 10 12 8 5.24 4952 690 1920 4 60 0 38 2 5.37 5047 719 1924 5 50 25 20 5 5.20 4795 683 1902 6 50 32 13 5 5.19 4807 683 1912 7 52 15 30 3 5.31 4921 703 1909 8 85 7 0 8 5.47 5289 725 1946 9 65 15 15 5 5.26 4980 707 1936 10 50 25 25 0 5.31 4994 718 1941

[0048] As apparent from the above description, the present invention provides a refrigerant composition, which is useful as a substitute for HCFC-22, produced by mixing additionally any one component of RC-270, HFC-227ea, HFC-245cb, R-600a, RC-318, HFC-236ea, R-600, HFE-134 and HFE-245 with a mixture of HFC-32, HFC-125 and HFC-143a. The refrigerant composition according to the present invention has an advantage in that it does not damage the ozone layer, so there is no possibility of restricted in use in the future. The above materials, which are components of the refrigerant composition according to the present invention, are currently commercially available, or active research for those materials is being conducted to make them commercially available in the near future.

[0049] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalence of such meets and bounds are therefore intended to be embraced by the appended claims. 

What is claimed is:
 1. A refrigerant composition useful as a substitute for chlorodifluoromethane, comprising: a first constituent of difluoromethane; a second constituent of pentafluoroethane; a third constituent of 1,1,1-trifluoroethane; a fourth constituent selected from the group consisting of cyclopropane, 1,1,1,2,3,3,3-heptafluoropropane, 1,1,1,2,2-pentafluoropropane, isobutane, octafluorocyclobutane, 1,1,1,2,3,3-hexafluoropropane, butane, bis(difluoromethyl)ether and pentafluoroethylmethylether.
 2. The refrigerant composition according to claim 1, wherein the first constituent is 15 to 95 by weight, the second constituent is present in an amount up to 60% by weight, the third constituent is present in an amount up to 70% by weight, and the fourth constituent is present in an amount up to 50% by weight.
 3. The refrigerant composition according to claim 1, wherein said composition comprises 25 to 45% by weight of difluoromethane, 2 to 35% by weight of pentafluorethane, 28 to 60% by weight of 1,1,1-trifluoroethane and an amount up to 10% by weight of cyclopropane.
 4. The refrigerant composition according to claim 1, wherein said composition comprises 28 to 50% by weight of difluoromethane, 2 to 50% by weight of pentafluoroethane, 5 to 60% by weight of 1,1,1-trifluoroethane and an amount up to 40% by weight of 1,1,1,2,3,3,3-heptafluoropropane.
 5. The refrigerant composition according to claim 1, wherein said composition comprises 30 to 85% by weight of difluoromethane, 2 to 45% by weight of pentafluoroethane, 3 to 50% by weight of 1,1,1-trifluoroethane and an amount up to 40% by weight of 1,1,1,2,2-pentafluoropropane.
 6. The refrigerant composition according to claim 1, wherein said composition comprises 38 to 50% by weight of difluoromethane, 5 to 35% by weight of pentafluoroethane, 20 to 43% by weight of 1,1,1-trifluoroethane and an amount up to 15% by weight of isobutane.
 7. The refrigerant composition according to claim 1, wherein said composition comprises 30 to 48% by weight of difluoromethane, 10 to 35% by weight of pentafluoroethane, 20 to 40% by weight of 1,1,1-trifluoroethane and an amount up to 15% by weight of octafluorocyclobutane.
 8. The refrigerant composition according to claim 1, wherein said composition comprises 30 to 75% by weight of difluoromethane, 5 to 30% by weight of pentafluoroethane, 5 to 48% by weight of 1,1,1-trifluoroethane and an amount up to 20% by weight of 1,1,1,2,3,3-hexafluoropropane.
 9. The refrigerant composition according to claim 1, wherein said composition comprises 35 to 60% by weight of difluoromethane, 5 to 50% by weight of pentafluoroethane, 5 to 33% by weight of 1,1,1-trifluoroethane and an amount up to 12% by weight of butane.
 10. The refrigerant composition according to claim 1, wherein said composition comprises 40 to 88% by weight of difluoromethane, 2 to 40% by weight of pentafluoroethane, 2 to 30% by weight of 1,1,1-trifluoroethane and an amount up to 10% by weight of bis(difluoromethyl)ether.
 11. The refrigerant composition according to claim 1, wherein said composition comprises 40 to 85% by weight of difluoromethane, 5 to 40% by weight of pentafluoroethane, 5 to 38% by weight of 1,1,1-trifluoroethane and an amount up to 10% by weight of pentanfluoroethylmethylether. 